Mom's 2000 TDI had an intermittent CEL and code P3130, EGR Regulation Exceeded, code stored. Since her car just became subject to OBD II emissions testing (just enacted in Northern Virginia for diesel cars w/ OBD II systems), I decided to take a look.

I think I have solved the problem.

I originally noticed, using VAG-COM, that on idle air requested was about 275 MG/Stroke and actual was about double that. Hmmm, the EGR system must be clogged, I thought. I cleaned out a plugged up EGR cooler, and a month later Mom said the CEL came on again. Air requested was half of air actual again, and same P3130 code was stored. I noticed a cracking vacuum hose to the EGR valve, and replaced it. Two months later, same thing--CEL on again intermittently and the same P3130 code.

This time I checked the EGR valve. I would not hold vacuum applied to its diaphragm--It leaked badly. The valve was inoperative! I verified this by simply conecting a vacuum hose to the diaphragm nipple, and sucking on the hose. It leaked badly, and the valve pintle never raised.

Yesterday I installed a replacement EGR valve from IMPEX (I bought the less expensive non-VW one, but oddly, it was made by the same manufacturer-Whaler) for $168 (VW wanted $285 for an EGR valve!).

Now when idling, the actual and requested air amounts are virtually identical and after a minute, the EGR cuts off, like its supposed to and the actual air quantity (past the MAF) doubles, blip the throttle, actual and requested air amounts are then identical again. I doubt if the CEL will come back on.

Just something to check if you have the P3130 code. Overall, this code means that not enough exhaust is flowing into the intake through the EGR valve and this could be caused by several things. In Mom's case, it was a bad EGR valve diaphragm.

On a side note: When removing the old EGR alve, when pulling off the anti-shutter valve vacuum line, the plastic nipple broke clean off of the vacuum diaphragm, and with supprising little effort. This was not an issue, since the new EGR valve had the anti-shutter valve diaphragm on it. But, is there a replacement source for this plastic vacuum actuator for the anti-shutter valve, other than buying the whole EGR valve? That little plastic arm on the diaphragm can break too! Just wondering.

I used JB Weld epoxy to fix the actuator arm I broke. I had to replace the EGR with one from Impex as mine had a bad diaphram. A razor to cut off the hose might be better than breaking the fragile vacuum hose connector.

The plastic diaphragm nipple has a plastic collar surrounding it that the line slips into, so you can't get to the vacuum line to slit it. Most frustrating if you have to replace your vacuum lines, due to age, I would imagine!

The plastic diaphragm nipple has a plastic collar surrounding it that the line slips into, so you can't get to the vacuum line to slit it. Most frustrating if you have to replace your vacuum lines, due to age, I would imagine!

--Nate

There is a slot on the side of the collar that allows a small knife access to slice the tubing. Can't do it on the car, though. There is a solenoid on the back of the intake that controls vacuum to the anti-shudder actuator. Disconnect the solenoid vacuum line at the plastic "Y" behind the intake. Disconnect the wiring harness from the solenoid. Release the solenoid from it's mount, and remove the EGR and the solenoid as a unit. Now you can slit the hose and gently twist the hose to remove from the actuator.

Also, I would imagine any vacuum system problem would prevent the EGR valve from functioning, and also as well as the solinoid that modulates the vacuum to the EGR valve (or its electrical wiring short) could cause the same code.

Also, I would imagine any vacuum system problem would prevent the EGR valve from functioning, and also as well as the solinoid that modulates the vacuum to the EGR valve (or its electrical wiring short) could cause the same code.--Nate

I've had a couple of cars with bad solenoids. Electrical works, but the internal allowed either vacuum all the time, or never.